Mechanical and surface force nanoprobe

Abstract

A method and apparatus to use an Atomic Force Microscope to take measurements of surface forces, indentation, adhesion and mechanical properties such as hardness and elasticity. The force between a probe mounted cantilever and a sample is measured as a function cantilever deflection measured by a electron tunneling microscope. The sample and the tip of the tunneling microscope are each mounted on piezoelectric manipulators which provide for position control. Position of the sample and probe are measured from the voltages applied to the piezoelectric manipulators. Penetration is determined by the relative motion between the probe and sample. Presently, this invention has a force resolution of 1 nN and a depth resolution of 0.02 nm.

What is claimed is: 
     
       1. A method for using an Atomic Force Microscope (AFM) to measure a surface property of a sample, comprising: mounting a probe for said AFM on a Cantilever whose deflection is a function of the force applied to said probe;   placing said probe and said sample at a separation greater than the zero deflection range of said surface property to be measured;   reducing said separation to zero by moving said sample towards said probe;   using a deflection measuring means to measure said deflection of said cantilever as a function of the position of said sample; and   determining said surface property of said sample from said displacement.   
     
     
       2. The method of claim 1 wherein said deflection measuring means is electron tunneling. 
     
     
       3. The method of claim 1 wherein said deflection measuring means is an optical means. 
     
     
       4. The method of claim 1 wherein said deflection measuring means is a capacitance measuring means. 
     
     
       5. A method as in claim 1 wherein said measurement of a surface property, comprises the steps of; reversing the direction of travel of said sample until contact with said probe is broken;   determining surface force at each of a plurality of separations between the point of contact and the zero deflation separation from the measured deflection at that separation; and   recording surface force versus said separation.   
     
     
       6. A method as in claim 1 wherein said determining step comprises the steps of; determining the penetration of the probe into the sample from the relative motion of the probe and the sample;   reversing the direction of travel of the sample until contact with the probe is broken;   determining the applied force by applying the deflection function to the measured deflection; and   recording the penetration versus the applied force.